With the improved degree of semiconductor integration, there have recently been packages having arrayed electrodes, some of which have a class of 5000 pins. In many cases, array-type packages are soldered directly to a printed circuit board, as BGA (ball grid array). However, because of thermal stress cracking of solder on large packages, and demands of replacement and maintenance, there has been an increase in the use of the LGA (land grid array) method using a pressure-connected socket. For example, sizes of LGA packages have become large and electrode gap has been narrowed, so that electric connectors such as LGA sockets in response to this trend are demanded.
Furthermore, when wafer sizes are increased to 300 mm to 400 mm in diameter in view of productivity improvement of semiconductors, the number of electrodes to be simultaneously inspected is markedly increased to several thousands to several tens of thousands of pins. Therefore, electric connectors such as probes in semiconductor inspection apparatuses must be further narrowed in pitch in response to the thus enlarged wafers. On the other hand, because of the increased number of product types and the like, also, inspection apparatuses are requested which can be used by replacing only an electric connector of a wafer-side probe.
A connecting element of a thin-type LGA socket is used to connect such flat electrodes with each other, cantilever types are mainly used because of their spring characteristic, electric property and cost. As cantilever connectors require a certain length of a beam in an oblique rising direction to satisfy requirements of displacement and load, an array method of connecting elements has been developed as a response to the narrowed pitch.
Furthermore, a cantilever connector is characterized in that stable electric connection is obtained by breaking an oxide layer on a surface, while the end of a connecting element slides on a device electrode. However, when beams are oriented in the same direction in the case of super-multi-pins, a total sliding force is increased, which generates a large reaction between a device and a connector. In particular, when the base material portion of a connector is a film-like elastic body, sometimes the base material portion becomes undulated or transforms, which sometimes damages stable connection.
To solve such a problem, a method is disclosed in which the beam directions are opposite every two lines to totally balance the sliding force (patent documents 1, 2, 3, and the like).
Patent document 1: Specification, U.S. Pat. No. 6,293,808
Patent document 2: Specification, U.S. Pat. No. 6,971,885
Patent document 3: Bulletin, Japanese Unexamined Patent Application Publication No. 2006-49260